This invention relates to tape recorders which have, for instance, a function of automatically starting the recording when an audio signal is supplied, and automatically stopping the recording with the vanishment of the audio signal.
Taper recorders for recording dictations or the like are desirably provided with an automatic starter or actuator for preventing the wasting of the recording tape. Where the automatic actuator is provided, recording on the recording tape is made only when the voice pressure is given to the microphone. In this case, the running of the tape during a voice-free period, during which dictation is not given, is prevented. The tape recorder provided with an automatic actuator as described is disclosed in, for instance, in FIG. 7 of U.S. Pat. No. 4,120,009 (Oct. 10, 1978).
Such a tape recorder provided with an automatic actuator, however, has problems in that a leading portion of dictation immediately after the start of recording fails to be recorded and that the initial period after the start of recording is prone to the deviation of pitch. The failure of recording of the initial portion of dictation is attributable to a slight time delay that is involved from the instant when voice is coupled till the instant when the actual operation of the tape transporting mechanism is started. A motor and a capstan flywheel in the tape drive system have large inertia. Therefore, a slight period of time is involved from the start of the operation of the tape transporting mechanism till the reaching of a predetermined running speed by the tape. This causes the aforementioned deviation of pitch in the initial period from the start of recording.
Due to the aforementioned two problems, i.e., failure of recording of an initial portion of dictation and deviation of pitch, with a tape recorder which is provided with a mere automatic actuator the spoken voice in the initial stage from the start of the automatic recording cannot be entirely and accurately recorded. Particularly, consonants which are quite often included in an initial portion of dictation given from the start of the recording, are uttered in very short periods of time. Therefore, failure of correct recording of consonants uttered in an initial period from the start of recording is liable, making the content of the corresponding portion of the dictation very indistinct.